1. Field of the Invention
The present invention relates generally to light-emitting diode packaging technology, and more particularly to a light-emitting diode packaging apparatus, mold base of the light-emitting diode packaging apparatus, and supporting member applied to the light-emitting diode packaging apparatus.
2. Description of Related Art
Different from luminescence principle of incandescent lamps, light-emitting diodes (LEDs) emit light by applying currents on luminescent materials, which are accordingly called as cold light. As the LEDs have advantages of high durability, long life time, small volume, light weight, low power consumption and the LEDs do not contain hazardous substances such as mercury, solid state lighting using the LEDs has become a research focus of the global lighting industry and semiconductor industry. Generally, the LEDs can be applied in such as white lighting, indicator light, vehicle signal light, traffic light, flashlight, LED backlight module, projector light source, display and so on.
With development and application of high power LEDs having characteristics of smaller volume, high light density and maximum light extraction per unit area, the conventional LED matrix has been eliminated in LED lighting design and LED molding and packaging process has become a major factor in affecting luminescence efficiency of the high power LEDs. Particularly, when the LEDs are applied in industries such as vehicle light, signal light and traffic light that have some regulatory limitations and specifications on luminous intensity distribution and luminescence efficiency, high precision LED packaging is required. Taiwan Patent Publication No.326250, No.343036, and Certificate No. M285041 disclose designs related to LED packaging apparatus.
Referring to FIG. 1, a conventional LED packaging apparatus is used for a plurality of supporting pieces 11 of a supporting member 1 to be inserted therein for the subsequent molding and packaging process. All the supporting pieces 11 are arranged at interval and connected together by two connecting sheets 13. Each of the supporting pieces 11 has a pair of electrode pins 111 for electrically coupling with LEDs. The LED packaging apparatus substantially comprises a mold base 2 and a mold base carrier (not shown) for carrying the mold base 2. The mold base 2 comprises a silicon steel sheet 21 into which the supporting pieces 11 of the supporting member 1 can be inserted, a plurality of mold cups 23 fixed to the silicon steel sheet 21 at interval, a plurality of V-shaped stands 25 disposed on the silicon steel sheet 21 between adjacent mold cups 23, and guiding columns 27 disposed at two sides of the silicon steel sheet 21 and comprising guiding slots 271 for guiding the supporting member 1.
After the supporting member 1 is inserted into the mold base 2 and positioned thereto, processes of molding, roasting and mold releasing can be sequentially performed on the mold cups 23 so as to complete the packaging process. However, as the supporting pieces 11 of the supporting member 1 is indirectly positioned in front/back/right/left directions by the connecting sheets 13, the stands 25 and the guiding slots 271 of the guiding columns 27 instead of being directly positioned on the silicon steel sheet 21, the accumulated tolerances may cause problems such as package misalignment and unstable structure, especially if the guiding columns 27 are made of a plastic material. As the plastic material only has an injection precision of 0.2 mm, compared with 0.001 mm stamping precision of the silicon steel sheet, not only the accumulated tolerance is big, the expansion coefficient difference and softening phenomenon occurring during the roasting process also exacerbate the package misalignment problem. Further, the wearing of the guiding columns 27 of plastic material caused by repeatedly mold releasing processes can worsen the package misalignment problem, thereby resulting in low packaging yield and high fabrication cost.
Accordingly, Taiwan Patent Publication No.326250 discloses a positioning structure for LED packaging apparatus. As shown in FIG. 2, the LED packaging apparatus also comprises a mold base 4 and a mold base carrier (not shown) for carrying the mold base 4. The mold base 4 comprises a silicon steel sheet 41 into which the supporting member 3 can be inserted, a plurality of mold cups 43 fixed to the silicon steel sheet 41 at interval, and a plurality of V-shaped stands 45 disposed on the silicon steel sheet 41 between adjacent mold cups 43. Therein, the above-mentioned guiding columns 27 are omitted in the present patent. The plurality of supporting pieces 31 of the supporting member 3 are connected at interval to the two connecting sheets 33, and each of the supporting pieces 31 has a pair of electrode pins 311 for electrically coupling with LEDs. In addition, a clipping sheet 35 is formed between every two adjacent supporting pieces 31 by stamping such that when the supporting member 3 is disposed across the stands 45, the clipping sheets 35 can be crossly engaged with the Y-shaped stands 45, thereby positioning the supporting member 3 in front/back/right/left/down directions. Although the structure of the present patent is simple, because of the omitting of the guiding columns, the positioning of the supporting member 3 is easy to deflect. Meanwhile, as the supporting member 3 is not positioned in the up direction, the depth of the supporting member 31 can be changed and the structure can be unstable, thereby increasing or decreasing the luminescent angle of LEDs.
To overcome the above drawbacks, a controller is disclosed in Taiwan Certificate No.M285041. As shown in FIG. 3, the supporting member 1 and the mold base 2 are same as those in FIG. 1. The supporting member 1 comprises a plurality of supporting pieces 11 arranged at interval and connected together by two connecting sheets 13. Each of the supporting pieces 11 has a pair of electrode pins 111 for electrically coupling with LEDs. The LED packaging apparatus substantially comprises a mold base 2 and a mold base carrier 29 for carrying the mold base 2. The mold base 2 comprises a silicon steel sheet 21 into which the supporting pieces 11 of the supporting member 1 can be inserted, a plurality of mold cups 23 fixed to the silicon steel sheet 21 at interval, a plurality of V-shaped stands 25 disposed on the silicon steel sheet 21 between any two adjacent mold cups 23, and guiding columns 27 disposed at two sides of the silicon steel sheet 21 and comprising guiding slots 271 for guiding the supporting member 1. The design of the present patent is characterized in a controller 28 having a slot 281, wherein the controller 28 is pressed against the top of the supporting member 1 and fixed by the guiding columns 27.
Although the supporting member 1 can be positioned in up/down directions through the controller 28, the problem of accumulated tolerances still exists. That is, the accumulated tolerances caused by indirect positioning of the supporting member 1 on the silicon steel sheet 21 can lead to such problems as package misalignment and unstable structure. Especially if the guiding columns 27 are made of a plastic material only having injection precision of 0.2 mm, compared with 0.001 mm stamping precision of the silicon steel sheet, not only accumulated tolerance is big, the expansion coefficient difference and softening phenomenon occurring during the roasting process under the temperature of 150° C. also exacerbate the misalignment problem. Further, the wearing of the guiding columns 27 of plastic material caused by repeatedly mold releasing processes can worsen the package misalignment problem, thereby resulting in low packaging yield and high fabrication cost.
Therefore, how to overcome the above drawbacks has become critical.